The present invention relates to a paper sheet stacking apparatus for dividing continuously fed paper sheets into regular sheaves each consisting of a predetermined number of paper sheets, which comprises a blade wheel means rotating about a substantially horizontal axis of rotation, the vane wheel means having a plurality of blades extending from the central portion to the outer periphery thereof in the direction opposite to the rotating direction thereof, each two adjacent blades defining therebetween a space having an opening on the outer periphery of the blade wheel means, feeding means for continuously inserting the paper sheets into the spaces, one for each space, through the openings of the blade wheel means passing a predetermined receiving position, a stationary stop adapted to abut against the paper sheets held in the spaces and rotating together with the blade wheel means, thereby stopping the rotation of the paper sheets, so that the paper sheets are discharged from the spaces of the vane wheel means and dropped automatically, and main stacking means for receiving and bearing thereon the paper sheets discharged from the blade wheel means.
Paper sheet stacking apparatuses of this type are generally known. Paper sheets of documents, such as bank notes, data cards, printed matter, etc., are conventionally processed in a mechanized system. Since these documents have recently been increasing steadily, there is an urgent demand for the development of high-speed processing apparatuses for them.
For example, processing of bank notes includes a step of tying them up with bands or the like into bundles each consisting of a predetermined number of bank notes. In executing this process, it is not very efficient to manually divide the paper sheets into lots. Usually, therefore, the paper sheets are divided into regular sheaves each including a predetermined number of sheets on an automatic processing apparatus, and the sheaves are then tied up with bands. Such an automatic processing apparatus is preferably constructed so that the paper sheets fed one by one at high speed can continuously be stacked without interrupting the feed of the paper sheets, and that the division into the regular sheaves is achieved in the course of the stacking process.
Conventional paper sheet stacking means to fulfill these requirements include the so-called beating system, in which the paper sheets delivered from the delivery-side end of conveyor means and flying in the air are beaten down. In this stacking means, there is a limit to the high-speed response characteristic of direction changing means for the sheet papers. Since the cycle of the direction changing means is raised by high-speed vibration with constant amplitude, so the force of inertia is increased. Thus, the operation of the direction changing means becomes unstable, or the force applied to the mechanical part is increased. To cope with this, the apparatus is increased in size and therefore in cost. In the beating system, moreover, the force used in beating the paper sheets is so great that some of the paper sheets may be stacked in folded or torn states. Consequently, the beating system is not a suitable system for high-speed paper sheet stacking.
There is a system in which a blade wheel is used for stacking means to cover up these drawbacks. In this system, the blade wheel has a plurality of elongate blades extending from the central portion of the blade wheel in the direction opposite to the rotating direction and arranged along the circumference of the blade wheel. Paper sheets are fed into slender spaces formed between the blades of the blade wheel, rotated together with the blade wheel through a predetermined angle, and then discharged from the blade wheel at a predetermined position to be stacked in place. According to this system, if the number of the paper sheets per minute successively inserted into the slender spaces is N, then the revolution per minute of the blade wheel is n=N/m RPM , where m is the number of the spaces. In order words, the rotary speed n of the blade wheel is obtained by dividing the number of paper sheets to be fed per minute by the number of the spaces. This implies that the blade wheel is rotated relatively slowly. Even in a case such that, for example, 1,800 paper sheets are supplied every minute to the blade wheel, the rotary speed n of the blade wheel may be as low as 100 (rpm) if the spaces used are 18 in number. Accordingly, the blade wheel need not be rotated at high speed, and hence will not cause any trouble in high-speed paper sheet processing.
Thus, the blade wheel system has many advantages over the other stacking systems. Paper sheet stacking apparatuses have conventionally been proposed which combine the stacking means using the blade wheel with dividing means capable of dividing paper sheets into regular sheaves without interrupting the feed of the paper sheets. An example of such apparatuses is disclosed in Japanese Patent Application No. 26369/81. This apparatus is provided with a separator which includes an arm portion having an axis of rotation substantially in alignment with that of the blade wheel and extending from the axis to a position beyond the peripheral edge of the blade wheel along the side face thereof, and a receiving portion at the distal end of the arm portion. As the separator is rotated as required, paper sheets held individually in spaces of the blade wheel abut against the arm portion to be removed from the spaces. The removed paper sheets are temporarily held by the receiving portion. In the meantime, paper sheets previously removed by a stationary-stop-end stacked-on stacking means are delivered. Thereafter, the paper sheets on the receiving portion of the separator are transferred to the stacking means.
However, the conventional paper sheet stacking apparatus combining the blade-wheel stacking means and dividing means have the following problems. In temporarily receiving the paper sheets following a predetermined number of sheets by means of the separator, the arm portion of the separator is used as a stop for removing the aforesaid paper sheets from the spaces of the blade wheel, and the removed paper sheets are held by the receiving portion. Therefore, the arm portion is naturally located within the range of the width (along the axis of rotation of the blade wheel) of the paper sheets in the spaces of the blade wheel. Accordingly, when the separator is located in the section between the position for the feed of the paper sheets into the blade wheel and the position for the start of division or receiving, the depth of the spaces of the blade wheel is practically reduced by the existence of the arm portion. Thus, the rear edge portions of those paper sheets which are fed into the blade wheel while the separator is in the aforesaid intermediate section project from the spaces. The projecting portions will close the opening of each following space to receive the next paper sheet, thereby preventing the following paper sheet from entering its corresponding space. Thereupon, the rejected paper sheet will run against the one blocking its entrance and cause a jam. In order to avoid such an awkward situation, the interval of feed of the paper sheets into the blade wheel is inevitably lengthened, so that it is impossible to speed up the paper sheet processing. Further, the division of the paper sheets into the regular sheaves in stacking requires the separator to be rotated intermittently. The intermittent drive of the separator requires great power, so that the conventional stacking apparatus is high in power consumption.